Liu Hui, Osborne Colin P, Yin Deyi, Freckleton Robert P, Jiang Gaoming, Liu Meizhen
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
Center for Plant Ecology, Core Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
Oecologia. 2019 Sep;191(1):25-38. doi: 10.1007/s00442-019-04475-0. Epub 2019 Jul 25.
Phylogenetic analyses are essential for disentangling how environmental filtering and competition determine species coexistence across spatial scales. Inner Mongolia steppe has strong environmental gradients, but how the phylogenetic relatedness of co-occurring species and phylogenetic signals of functional traits change across spatial scales remains unclear. We investigated the phylogenetic structure of grass assemblages along environmental gradients from regional to local scales, and measured functional traits within assemblages. We compared phylogenetic signals of plant traits between the same numbers of species randomly selected from the regional pool and species observed at the local scale, did phylogenetic principal component analysis to infer the main factors driving species coexistence, and examined the key plant trait-environment relationships across the phylogeny to reveal ecological adaptation mechanisms. Regionally, grass species were phylogenetically clustered with contrasting climate preferences. With decreasing spatial scales, species richness declined, changing from phylogenetically clustered to overdispersed, and phylogenetic signals of plant traits became weaker. At the local scale, grass assemblages were structured by soil water content and neighbor density, and the trait-environment relationships were less clear than those at the regional scale. This study demonstrated that at smaller scales, co-occurring grass species in the steppe tended to be more phylogenetically overdispersed, and that phylogenetic signals of plant functional traits became weaker with increasing abiotic and biotic interactions. Our findings contributed evidence for understanding species coexistence and maintenance at scales spanning regional to local communities in the East Asia steppe biome.
系统发育分析对于理清环境过滤和竞争如何在不同空间尺度上决定物种共存至关重要。内蒙古草原具有强烈的环境梯度，但共存物种的系统发育相关性以及功能性状的系统发育信号如何随空间尺度变化仍不清楚。我们研究了从区域尺度到局部尺度沿环境梯度的禾本科植物群落的系统发育结构，并测量了群落内的功能性状。我们比较了从区域物种库中随机选择的相同数量物种与在局部尺度上观察到的物种之间植物性状的系统发育信号，进行了系统发育主成分分析以推断驱动物种共存的主要因素，并研究了整个系统发育中关键植物性状与环境的关系以揭示生态适应机制。在区域尺度上，禾本科物种在系统发育上聚类，具有不同的气候偏好。随着空间尺度的减小，物种丰富度下降，从系统发育聚类转变为过度分散，植物性状的系统发育信号变弱。在局部尺度上，禾本科植物群落由土壤含水量和邻体密度构建，且性状与环境的关系不如区域尺度上的清晰。本研究表明，在较小尺度上，草原中共存的禾本科物种在系统发育上往往更趋于过度分散，并且随着非生物和生物相互作用的增加，植物功能性状的系统发育信号变弱。我们的研究结果为理解东亚草原生物群落中从区域到局部群落尺度上的物种共存和维持提供了证据。
